1. Field of the Invention
The present invention relates to a platform door device.
2. Description of the Related Art
Heretofore, there has been known a platform door device installed along an edge of a platform on the side of a rail track in order to ensure safety of passengers. One example of such a platform door device is disclosed in JP 2006-240529A.
A platform door device disclosed in JP 2006-240529A comprises a door, a guiding mechanism, and a driving mechanism.
The door has a panel-shaped portion composed of a frame assembly and a glass plate set in the frame assembly. The door is adapted to be guided by the guiding mechanism in such a manner as to be movable forwardly and backwardly in a horizontal direction along an edge of a platform.
The guiding mechanism includes a linear rail attached to the frame assembly of the door so as to extend in a direction of the movement of the door, and a slide block fixed to an inside of a guide box installed on the platform and slidably provided to the linear rail.
The driving mechanism is provided inside the guide box and beneath the door. The driving mechanism includes a motor, a driving pulley, a pair of idler pulleys, and a toothed belt. The driving pulley has teeth, and is adapted to be rotated according to driving of the motor. The pair of idler pulleys are disposed to interpose the driving pulley therebetween. The toothed belt is wound over the pair of idler pulleys and meshed with the teeth of the driving pulley at a position between the idler pulleys. One end of the toothed belt is attached to a lower region of one end of the frame assembly in the movement direction of the door, through a bracket. The other end of the toothed belt is attached to a lower region of the other end of the frame assembly in the movement direction of the door, through a bracket. The toothed belt is held between the both ends of the frame assembly of the door, while being tightened with a given tension.
In the driving mechanism, the driving pulley is rotated according to driving of the motor, and thereby the toothed belt is moved. According to the movement of the toothed belt, the door is pulled and thereby moved forwardly or backwardly. Then, according to the forward and backward movements of the door, a gate on the platform is opened and closed.
In the above platform door device, in the event of damage to the panel-shaped portion of the door, the damaged door will be replaced with a new one. In this replacement operation, it is necessary to detach the toothed belt from the frame assembly. Then, after attaching a new door to the platform door device, and attaching the toothed belt between both ends of a lower portion of a frame assembly of the new door, it is necessary to perform adjustment of the driving mechanism, such as adjustment of belt tension. This causes a problem of an increase in time required for the replacement operation.